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Environment and Listener Optimised Speech Processing for Hearing Enhancement in Real Situations (ELO-SPHERES)
PIs: Mark Huckvale, Patrick Naylor and Stuart Rosen. Research Fellows include Tim Green and Gaston Hilkhuysen at UCL, and Alastair Moore, Sina Hafezi, Xue Wang, Rebecca Vos and Pierre Guiraud at Imperial College. Ended March 2023.
This project aimed to better understand the problems of hearing impaired listeners in noisy, multiple-talker conversations, particularly with regard to (i) their abilities to attend to and recognise speech coming from different directions while listening through binaural hearing aids, (ii) their use of audio-visual cues. We developed new techniques for coordinated processing of the signals arriving at the different ears from hearing aids that allow the identification of the locations and characteristics of different sound sources in complex environments and tailor the information presented to match the individual listener's pattern of hearing loss. We built virtual reality simulations of complex listening environments and have developed audio-visual tests to assess the abilities of listeners.
For a more extensive description of the project, see https://speechandhearing.net/project/elospheres/
Consequences of cochlear neuropathy in people with normal hearing thresholds
Researchers: Stuart Rosen, Tim Schoof, Tim Green, Andrew Faulkner. Action on Hearing Loss International Project Grant 2017 - 2020.
Many people experience difficulties understanding speech in noise even in the absence of any hearing loss. One possible explanation for these difficulties may be that, either as a consequence of noise exposure or ageing, these individuals show some damage to the synapses between the inner hair cells and the auditory nerve fibres, or to the auditory nerve fibres themselves. Animal studies have shown that this damage, called cochlear neuropathy or ‘hidden hearing loss’, has a greater effect on nerve fibres specialised for high rather than low sound levels, which is one reason why the damage is not reflected in increased audiometric thresholds. In consequence, there may be enough information to tell that a sound is present, but the details of that sound (for example, its pitch and quality) will be degraded. While evidence for cochlear neuropathy in humans is emerging, its consequences for auditory processing remain unclear. In particular, we will investigate the effects of cochlear neuropathy on auditory temporal processing and speech perception in noise in young and middle-aged adults with normal audiometric thresholds.
Listening effort in users of cochlear implants
Researchers: Stuart Rosen, Debi Vickers, Helen Willis. Action on Hearing Loss PhD studentship to Helen Willis. October 2014 - September 2017
A common complaint amongst the hearing impaired is that of increased listening effort (LE: the cognitive resource necessary for speech understanding). Increased LE has debilitative long term health consequences. This issue has only just begun to be explored in the cochlear implant (CI) population. Furthermore, current emphasis of clinical assessment during CI rehabilitation is speech comprehension. Considering LE’s impact on patients’ physical wellbeing, a clinical measurement of LE is essential. By the investigation of four participant groups (newly implanted CI recipients to be studied over the course of 9 months; experienced CI recipients after tuning; CI recipients where remapping has been induced; and controls listening to CI simulations), the impact of LE during key phases of CI rehabilitation will be assessed. This will assist in evaluating which behavioural measure of LE (dual-task paradigm or subjective ratings) is the most sensitive (validated against a physiological measure of LE: pupil dilation), from which a clinical test can be developed. Having a clinical test of LE would ultimately promote better rehabilitation outcomes, for physical wellbeing as well as speech comprehension, because there would then be an accurate measurement of the cognitive cost in the CI recipients’ speech processing and their capacity to improve.
Environment-aware Listener-Optimized Binaural Enhancement of Speech (E-LOBES)
Researchers: Mark Huckvale, Stuart Rosen, Tim Green, Gaston Hilkhuysen (UCL); Mike Brookes, Patrick Naylor, Enzo De Sena, Leo Lightburn (Imperial College). Ended August 2018
Age-related hearing loss affects over half the UK population aged over 60. Hearing loss makes communication difficult and so has severe negative consequences for quality of life. The most common treatment for mild-to-moderate hearing loss is the use of hearing aids. However even with aids, hearing impaired listeners are worse at understanding speech in noisy environments because their auditory system is less good at separating wanted speech from unwanted noise. One solution for this is to use speech enhancement algorithms to amplify the desired speech signals selectively while attenuating the unwanted background noise.
Pitch perception and production in children with cochlear implants
Deafness Research UK studentship to Lucy Carroll; supervisors Andrew Faulkner and Debi Vickers (UCL Ear Institute).
Duration 3 years: October 2011-September 2014
Pitch processing is widely thought to play an important role in speech and language development, yet children developing speech and language through auditory input from a CI may be impeded in this because they do not receive sufficiently good pitch information. This project is studying a sample of at minimum 20 children with cochlear implants aged 6-10 to characterise their pitch processing for speech-like sounds and investigate the relations of pitch processing to prosodic processing and language development.
Auditory brainstem responses to speech sounds in quiet and noise: The effects of ageing and hearing impairment
Action on Hearing Loss studentship to Tim Schoof. Supervisors: Stuart Rosen and Ifat Yasin (UCL Ear Institute). Duration 4 years: October 2010 – September 2014.
Older people often complain about the difficulty of understanding speech in the presence of background noises, whether they are hearing impaired or not. We are investigating the extent to which the fidelity and distinctiveness of neural representations of speech sounds at the auditory nerve and brain stem level are related to abilities to understand speech in noise, and how they change with hearing impairment and age. Auditory brainstem responses reflect neural activity from the auditory nerve up to the midbrain and retain much of the temporal complexity of speech, so are well suited to assess the extent to which important speech features are preserved at this early level of processing. Our goal is to understand the extent to which difficulties in understanding speech in background noises can arise from deficits in auditory encoding at the first neural stages of the auditory pathway, and so provide guidance to future methods of diagnosis and rehabilitation.
The bases of benefit from bimodal combinations of cochlear implant and hearing aid
Researchers: Andrew Faulkner, Tim Green, Marine Ardoint, Stuart Rosen. Funded by Action on Hearing Loss (formerly RNID). Duration 3 years: November 2010 - September 2013.
Many cochlear implant users enjoy improved speech perception, particularly in noise, from using a contralateral hearing aid. However, uncertainty remains regarding the sources of bimodal benefit. The project seeks to further develop our understanding of factors underlying bimodal benefit, helping to establish clinically applicable methods for optimally combining an implant and a contralateral hearing aid and extending the population of implant users able to benefit from residual hearing.